a battery can take many servos, the reason i asked is if you were only using a micro servos to scan a sensor you could just power it from the USB as the power drain would be so low due to a very small load and a small servo.
the only thing that will effect the battery by adding more servos is the amount of time that charge will last. what is your battery? voltage, mAh rating, chemistry?
as for the sensors. most sensors will return a voltage as a reading, therefore you need to plug it into an analog port. then the micro controller takes that voltage reading and converts it into a digital value for the micro controller to understand, thus the saying ADC (analog to digital converter)
and what you said about power to 5v, GND to the GND and then the signal wire to one of the available analog pins.